The effect of six promoter-intron combinations on transient expression of beta-glucuronidase (GUS) as the reporter gene was estimated in cultured einkorn (Tuiticum monococcum), emmer (Triticum durum) and common (Triticum aestivum) wheat cell lines. Four promoters; cauliflower mosaic virus (CaMV) 35S, tandem CaMV35S, maize alcohol dehydrogenase gene (Adh1) and rice actin gene (Act1) promoters, and two introns; Adh1 intron 1 and castor bean catalase intron, were tested. Six vectors having different promoter-intron combinations were introduced into wheat cells by using particle bombardment. Different levels of GUS gene activity in three wheat calli were detected by an in situ enzyme assay. The CaMV35S promoter gave the lowest level of transient expression in wheat cells. On the other hand, the rice Act1 promoter showed the highest level of transient expression in all three wheat cells and was also the most efficient promoter of all, suggesting that the rice Act1 promoter is efficient for use in wheat transformation.
